let isDone: boolean = true

// 使用构造函数Boolean创造的对象不是布尔值
// let createByBoolean:boolean = new Boolean(1)
let createByBoolean: boolean = Boolean(1)

// 数值类型
let num: number = 6
let notanumber: number = NaN
let infinityNumber: number = Infinity

// 字符串

let myName:string = '薄荷er'
let content:string = `我是${myName}`

let add = (a:number, b:number) :number => a + b

// 空值,如果返回值是控制的话，void
function sayName(name:string) :void{
    console.log(name);
}

var value:void;
value = null;
value = undefined;

let u:undefined = undefined;
let n:null = null;

// undefined和null是所有类型的子类型
myName = undefined;
myName = null;
